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Maven plugin for generating graphql clients
/* @flow */
/**
* Copyright (c) 2015, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
import { forEach, isCollection } from 'iterall';
import { GraphQLError, locatedError } from '../error';
import invariant from '../jsutils/invariant';
import isNullish from '../jsutils/isNullish';
import { typeFromAST } from '../utilities/typeFromAST';
import * as Kind from '../language/kinds';
import {
getVariableValues,
getArgumentValues,
getDirectiveValues,
} from './values';
import {
GraphQLObjectType,
GraphQLList,
GraphQLNonNull,
isAbstractType,
isLeafType,
} from '../type/definition';
import type {
GraphQLType,
GraphQLLeafType,
GraphQLAbstractType,
GraphQLField,
GraphQLFieldResolver,
GraphQLResolveInfo,
ResponsePath,
} from '../type/definition';
import { GraphQLSchema } from '../type/schema';
import {
SchemaMetaFieldDef,
TypeMetaFieldDef,
TypeNameMetaFieldDef,
} from '../type/introspection';
import {
GraphQLIncludeDirective,
GraphQLSkipDirective,
} from '../type/directives';
import type {
DocumentNode,
OperationDefinitionNode,
SelectionSetNode,
FieldNode,
FragmentSpreadNode,
InlineFragmentNode,
FragmentDefinitionNode,
} from '../language/ast';
/**
* Terminology
*
* "Definitions" are the generic name for top-level statements in the document.
* Examples of this include:
* 1) Operations (such as a query)
* 2) Fragments
*
* "Operations" are a generic name for requests in the document.
* Examples of this include:
* 1) query,
* 2) mutation
*
* "Selections" are the definitions that can appear legally and at
* single level of the query. These include:
* 1) field references e.g "a"
* 2) fragment "spreads" e.g. "...c"
* 3) inline fragment "spreads" e.g. "...on Type { a }"
*/
/**
* Data that must be available at all points during query execution.
*
* Namely, schema of the type system that is currently executing,
* and the fragments defined in the query document
*/
export type ExecutionContext = {
schema: GraphQLSchema;
fragments: {[key: string]: FragmentDefinitionNode};
rootValue: mixed;
contextValue: mixed;
operation: OperationDefinitionNode;
variableValues: {[key: string]: mixed};
fieldResolver: GraphQLFieldResolver;
errors: Array;
};
/**
* The result of GraphQL execution.
*
* - `errors` is included when any errors occurred as a non-empty array.
* - `data` is the result of a successful execution of the query.
*/
export type ExecutionResult = {
errors?: Array;
data?: ?{[key: string]: mixed};
};
/**
* Implements the "Evaluating requests" section of the GraphQL specification.
*
* Returns a Promise that will eventually be resolved and never rejected.
*
* If the arguments to this function do not result in a legal execution context,
* a GraphQLError will be thrown immediately explaining the invalid input.
*
* Accepts either an object with named arguments, or individual arguments.
*/
declare function execute({|
schema: GraphQLSchema,
document: DocumentNode,
rootValue?: mixed,
contextValue?: mixed,
variableValues?: ?{[key: string]: mixed},
operationName?: ?string,
fieldResolver?: ?GraphQLFieldResolver
|}, ..._: []): Promise;
/* eslint-disable no-redeclare */
declare function execute(
schema: GraphQLSchema,
document: DocumentNode,
rootValue?: mixed,
contextValue?: mixed,
variableValues?: ?{[key: string]: mixed},
operationName?: ?string,
fieldResolver?: ?GraphQLFieldResolver
): Promise;
export function execute(
argsOrSchema,
document,
rootValue,
contextValue,
variableValues,
operationName,
fieldResolver
) {
// Extract arguments from object args if provided.
const args = arguments.length === 1 ? argsOrSchema : undefined;
const schema = args ? args.schema : argsOrSchema;
return args ?
executeImpl(
schema,
args.document,
args.rootValue,
args.contextValue,
args.variableValues,
args.operationName,
args.fieldResolver
) :
executeImpl(
schema,
document,
rootValue,
contextValue,
variableValues,
operationName,
fieldResolver
);
}
function executeImpl(
schema,
document,
rootValue,
contextValue,
variableValues,
operationName,
fieldResolver
) {
// If arguments are missing or incorrect, throw an error.
assertValidExecutionArguments(
schema,
document,
variableValues
);
// If a valid context cannot be created due to incorrect arguments,
// a "Response" with only errors is returned.
let context;
try {
context = buildExecutionContext(
schema,
document,
rootValue,
contextValue,
variableValues,
operationName,
fieldResolver
);
} catch (error) {
return Promise.resolve({ errors: [ error ] });
}
// Return a Promise that will eventually resolve to the data described by
// The "Response" section of the GraphQL specification.
//
// If errors are encountered while executing a GraphQL field, only that
// field and its descendants will be omitted, and sibling fields will still
// be executed. An execution which encounters errors will still result in a
// resolved Promise.
return Promise.resolve(
executeOperation(context, context.operation, rootValue)
).then(data => context.errors.length === 0 ?
{ data } :
{ errors: context.errors, data }
);
}
/**
* Given a ResponsePath (found in the `path` entry in the information provided
* as the last argument to a field resolver), return an Array of the path keys.
*/
export function responsePathAsArray(
path: ResponsePath
): Array {
const flattened = [];
let curr = path;
while (curr) {
flattened.push(curr.key);
curr = curr.prev;
}
return flattened.reverse();
}
/**
* Given a ResponsePath and a key, return a new ResponsePath containing the
* new key.
*/
export function addPath(prev: ResponsePath, key: string | number) {
return { prev, key };
}
/**
* Essential assertions before executing to provide developer feedback for
* improper use of the GraphQL library.
*/
export function assertValidExecutionArguments(
schema: GraphQLSchema,
document: DocumentNode,
rawVariableValues: ?{[key: string]: mixed}
): void {
invariant(schema, 'Must provide schema');
invariant(document, 'Must provide document');
invariant(
schema instanceof GraphQLSchema,
'Schema must be an instance of GraphQLSchema. Also ensure that there are ' +
'not multiple versions of GraphQL installed in your node_modules directory.'
);
// Variables, if provided, must be an object.
invariant(
!rawVariableValues || typeof rawVariableValues === 'object',
'Variables must be provided as an Object where each property is a ' +
'variable value. Perhaps look to see if an unparsed JSON string ' +
'was provided.'
);
}
/**
* Constructs a ExecutionContext object from the arguments passed to
* execute, which we will pass throughout the other execution methods.
*
* Throws a GraphQLError if a valid execution context cannot be created.
*/
export function buildExecutionContext(
schema: GraphQLSchema,
document: DocumentNode,
rootValue: mixed,
contextValue: mixed,
rawVariableValues: ?{[key: string]: mixed},
operationName: ?string,
fieldResolver: ?GraphQLFieldResolver
): ExecutionContext {
const errors: Array = [];
let operation: ?OperationDefinitionNode;
const fragments: {[name: string]: FragmentDefinitionNode} =
Object.create(null);
document.definitions.forEach(definition => {
switch (definition.kind) {
case Kind.OPERATION_DEFINITION:
if (!operationName && operation) {
throw new GraphQLError(
'Must provide operation name if query contains multiple operations.'
);
}
if (!operationName ||
definition.name && definition.name.value === operationName) {
operation = definition;
}
break;
case Kind.FRAGMENT_DEFINITION:
fragments[definition.name.value] = definition;
break;
default: throw new GraphQLError(
`GraphQL cannot execute a request containing a ${definition.kind}.`,
[ definition ]
);
}
});
if (!operation) {
if (operationName) {
throw new GraphQLError(`Unknown operation named "${operationName}".`);
} else {
throw new GraphQLError('Must provide an operation.');
}
}
const variableValues = getVariableValues(
schema,
operation.variableDefinitions || [],
rawVariableValues || {}
);
return {
schema,
fragments,
rootValue,
contextValue,
operation,
variableValues,
fieldResolver: fieldResolver || defaultFieldResolver,
errors,
};
}
/**
* Implements the "Evaluating operations" section of the spec.
*/
function executeOperation(
exeContext: ExecutionContext,
operation: OperationDefinitionNode,
rootValue: mixed
): ?{[key: string]: mixed} {
const type = getOperationRootType(exeContext.schema, operation);
const fields = collectFields(
exeContext,
type,
operation.selectionSet,
Object.create(null),
Object.create(null)
);
const path = undefined;
// Errors from sub-fields of a NonNull type may propagate to the top level,
// at which point we still log the error and null the parent field, which
// in this case is the entire response.
//
// Similar to completeValueCatchingError.
try {
const result = operation.operation === 'mutation' ?
executeFieldsSerially(exeContext, type, rootValue, path, fields) :
executeFields(exeContext, type, rootValue, path, fields);
const promise = getPromise(result);
if (promise) {
return promise.then(undefined, error => {
exeContext.errors.push(error);
return Promise.resolve(null);
});
}
return result;
} catch (error) {
exeContext.errors.push(error);
return null;
}
}
/**
* Extracts the root type of the operation from the schema.
*/
export function getOperationRootType(
schema: GraphQLSchema,
operation: OperationDefinitionNode
): GraphQLObjectType {
switch (operation.operation) {
case 'query':
return schema.getQueryType();
case 'mutation':
const mutationType = schema.getMutationType();
if (!mutationType) {
throw new GraphQLError(
'Schema is not configured for mutations',
[ operation ]
);
}
return mutationType;
case 'subscription':
const subscriptionType = schema.getSubscriptionType();
if (!subscriptionType) {
throw new GraphQLError(
'Schema is not configured for subscriptions',
[ operation ]
);
}
return subscriptionType;
default:
throw new GraphQLError(
'Can only execute queries, mutations and subscriptions',
[ operation ]
);
}
}
/**
* Implements the "Evaluating selection sets" section of the spec
* for "write" mode.
*/
function executeFieldsSerially(
exeContext: ExecutionContext,
parentType: GraphQLObjectType,
sourceValue: mixed,
path: ResponsePath,
fields: {[key: string]: Array}
): Promise<{[key: string]: mixed}> {
return Object.keys(fields).reduce(
(prevPromise, responseName) => prevPromise.then(results => {
const fieldNodes = fields[responseName];
const fieldPath = addPath(path, responseName);
const result = resolveField(
exeContext,
parentType,
sourceValue,
fieldNodes,
fieldPath
);
if (result === undefined) {
return results;
}
const promise = getPromise(result);
if (promise) {
return promise.then(resolvedResult => {
results[responseName] = resolvedResult;
return results;
});
}
results[responseName] = result;
return results;
}),
Promise.resolve({})
);
}
/**
* Implements the "Evaluating selection sets" section of the spec
* for "read" mode.
*/
function executeFields(
exeContext: ExecutionContext,
parentType: GraphQLObjectType,
sourceValue: mixed,
path: ResponsePath,
fields: {[key: string]: Array}
): {[key: string]: mixed} {
let containsPromise = false;
const finalResults = Object.keys(fields).reduce(
(results, responseName) => {
const fieldNodes = fields[responseName];
const fieldPath = addPath(path, responseName);
const result = resolveField(
exeContext,
parentType,
sourceValue,
fieldNodes,
fieldPath
);
if (result === undefined) {
return results;
}
results[responseName] = result;
if (getPromise(result)) {
containsPromise = true;
}
return results;
},
Object.create(null)
);
// If there are no promises, we can just return the object
if (!containsPromise) {
return finalResults;
}
// Otherwise, results is a map from field name to the result
// of resolving that field, which is possibly a promise. Return
// a promise that will return this same map, but with any
// promises replaced with the values they resolved to.
return promiseForObject(finalResults);
}
/**
* Given a selectionSet, adds all of the fields in that selection to
* the passed in map of fields, and returns it at the end.
*
* CollectFields requires the "runtime type" of an object. For a field which
* returns an Interface or Union type, the "runtime type" will be the actual
* Object type returned by that field.
*/
export function collectFields(
exeContext: ExecutionContext,
runtimeType: GraphQLObjectType,
selectionSet: SelectionSetNode,
fields: {[key: string]: Array},
visitedFragmentNames: {[key: string]: boolean}
): {[key: string]: Array} {
for (let i = 0; i < selectionSet.selections.length; i++) {
const selection = selectionSet.selections[i];
switch (selection.kind) {
case Kind.FIELD:
if (!shouldIncludeNode(exeContext, selection)) {
continue;
}
const name = getFieldEntryKey(selection);
if (!fields[name]) {
fields[name] = [];
}
fields[name].push(selection);
break;
case Kind.INLINE_FRAGMENT:
if (!shouldIncludeNode(exeContext, selection) ||
!doesFragmentConditionMatch(exeContext, selection, runtimeType)) {
continue;
}
collectFields(
exeContext,
runtimeType,
selection.selectionSet,
fields,
visitedFragmentNames
);
break;
case Kind.FRAGMENT_SPREAD:
const fragName = selection.name.value;
if (visitedFragmentNames[fragName] ||
!shouldIncludeNode(exeContext, selection)) {
continue;
}
visitedFragmentNames[fragName] = true;
const fragment = exeContext.fragments[fragName];
if (!fragment ||
!doesFragmentConditionMatch(exeContext, fragment, runtimeType)) {
continue;
}
collectFields(
exeContext,
runtimeType,
fragment.selectionSet,
fields,
visitedFragmentNames
);
break;
}
}
return fields;
}
/**
* Determines if a field should be included based on the @include and @skip
* directives, where @skip has higher precidence than @include.
*/
function shouldIncludeNode(
exeContext: ExecutionContext,
node: FragmentSpreadNode | FieldNode | InlineFragmentNode,
): boolean {
const skip = getDirectiveValues(
GraphQLSkipDirective,
node,
exeContext.variableValues
);
if (skip && skip.if === true) {
return false;
}
const include = getDirectiveValues(
GraphQLIncludeDirective,
node,
exeContext.variableValues
);
if (include && include.if === false) {
return false;
}
return true;
}
/**
* Determines if a fragment is applicable to the given type.
*/
function doesFragmentConditionMatch(
exeContext: ExecutionContext,
fragment: FragmentDefinitionNode | InlineFragmentNode,
type: GraphQLObjectType
): boolean {
const typeConditionNode = fragment.typeCondition;
if (!typeConditionNode) {
return true;
}
const conditionalType = typeFromAST(exeContext.schema, typeConditionNode);
if (conditionalType === type) {
return true;
}
if (isAbstractType(conditionalType)) {
return exeContext.schema.isPossibleType(conditionalType, type);
}
return false;
}
/**
* This function transforms a JS object `{[key: string]: Promise}` into
* a `Promise<{[key: string]: T}>`
*
* This is akin to bluebird's `Promise.props`, but implemented only using
* `Promise.all` so it will work with any implementation of ES6 promises.
*/
function promiseForObject(
object: {[key: string]: Promise}
): Promise<{[key: string]: T}> {
const keys = Object.keys(object);
const valuesAndPromises = keys.map(name => object[name]);
return Promise.all(valuesAndPromises).then(
values => values.reduce((resolvedObject, value, i) => {
resolvedObject[keys[i]] = value;
return resolvedObject;
}, Object.create(null))
);
}
/**
* Implements the logic to compute the key of a given field's entry
*/
function getFieldEntryKey(node: FieldNode): string {
return node.alias ? node.alias.value : node.name.value;
}
/**
* Resolves the field on the given source object. In particular, this
* figures out the value that the field returns by calling its resolve function,
* then calls completeValue to complete promises, serialize scalars, or execute
* the sub-selection-set for objects.
*/
function resolveField(
exeContext: ExecutionContext,
parentType: GraphQLObjectType,
source: mixed,
fieldNodes: Array,
path: ResponsePath
): mixed {
const fieldNode = fieldNodes[0];
const fieldName = fieldNode.name.value;
const fieldDef = getFieldDef(exeContext.schema, parentType, fieldName);
if (!fieldDef) {
return;
}
const resolveFn = fieldDef.resolve || exeContext.fieldResolver;
const info = buildResolveInfo(
exeContext,
fieldDef,
fieldNodes,
parentType,
path
);
// Get the resolve function, regardless of if its result is normal
// or abrupt (error).
const result = resolveFieldValueOrError(
exeContext,
fieldDef,
fieldNodes,
resolveFn,
source,
info
);
return completeValueCatchingError(
exeContext,
fieldDef.type,
fieldNodes,
info,
path,
result
);
}
export function buildResolveInfo(
exeContext: ExecutionContext,
fieldDef: GraphQLField<*, *>,
fieldNodes: Array,
parentType: GraphQLObjectType,
path: ResponsePath
): GraphQLResolveInfo {
// The resolve function's optional fourth argument is a collection of
// information about the current execution state.
return {
fieldName: fieldNodes[0].name.value,
fieldNodes,
returnType: fieldDef.type,
parentType,
path,
schema: exeContext.schema,
fragments: exeContext.fragments,
rootValue: exeContext.rootValue,
operation: exeContext.operation,
variableValues: exeContext.variableValues,
};
}
// Isolates the "ReturnOrAbrupt" behavior to not de-opt the `resolveField`
// function. Returns the result of resolveFn or the abrupt-return Error object.
export function resolveFieldValueOrError(
exeContext: ExecutionContext,
fieldDef: GraphQLField,
fieldNodes: Array,
resolveFn: GraphQLFieldResolver,
source: TSource,
info: GraphQLResolveInfo
): Error | mixed {
try {
// Build a JS object of arguments from the field.arguments AST, using the
// variables scope to fulfill any variable references.
// TODO: find a way to memoize, in case this field is within a List type.
const args = getArgumentValues(
fieldDef,
fieldNodes[0],
exeContext.variableValues
);
// The resolve function's optional third argument is a context value that
// is provided to every resolve function within an execution. It is commonly
// used to represent an authenticated user, or request-specific caches.
const context = exeContext.contextValue;
return resolveFn(source, args, context, info);
} catch (error) {
// Sometimes a non-error is thrown, wrap it as an Error for a
// consistent interface.
return error instanceof Error ? error : new Error(error);
}
}
// This is a small wrapper around completeValue which detects and logs errors
// in the execution context.
function completeValueCatchingError(
exeContext: ExecutionContext,
returnType: GraphQLType,
fieldNodes: Array,
info: GraphQLResolveInfo,
path: ResponsePath,
result: mixed
): mixed {
// If the field type is non-nullable, then it is resolved without any
// protection from errors, however it still properly locates the error.
if (returnType instanceof GraphQLNonNull) {
return completeValueWithLocatedError(
exeContext,
returnType,
fieldNodes,
info,
path,
result
);
}
// Otherwise, error protection is applied, logging the error and resolving
// a null value for this field if one is encountered.
try {
const completed = completeValueWithLocatedError(
exeContext,
returnType,
fieldNodes,
info,
path,
result
);
const promise = getPromise(completed);
if (promise) {
// If `completeValueWithLocatedError` returned a rejected promise, log
// the rejection error and resolve to null.
// Note: we don't rely on a `catch` method, but we do expect "thenable"
// to take a second callback for the error case.
return promise.then(undefined, error => {
exeContext.errors.push(error);
return Promise.resolve(null);
});
}
return completed;
} catch (error) {
// If `completeValueWithLocatedError` returned abruptly (threw an error),
// log the error and return null.
exeContext.errors.push(error);
return null;
}
}
// This is a small wrapper around completeValue which annotates errors with
// location information.
function completeValueWithLocatedError(
exeContext: ExecutionContext,
returnType: GraphQLType,
fieldNodes: Array,
info: GraphQLResolveInfo,
path: ResponsePath,
result: mixed
): mixed {
try {
const completed = completeValue(
exeContext,
returnType,
fieldNodes,
info,
path,
result
);
const promise = getPromise(completed);
if (promise) {
return promise.then(
undefined,
error => Promise.reject(
locatedError(error, fieldNodes, responsePathAsArray(path))
)
);
}
return completed;
} catch (error) {
throw locatedError(error, fieldNodes, responsePathAsArray(path));
}
}
/**
* Implements the instructions for completeValue as defined in the
* "Field entries" section of the spec.
*
* If the field type is Non-Null, then this recursively completes the value
* for the inner type. It throws a field error if that completion returns null,
* as per the "Nullability" section of the spec.
*
* If the field type is a List, then this recursively completes the value
* for the inner type on each item in the list.
*
* If the field type is a Scalar or Enum, ensures the completed value is a legal
* value of the type by calling the `serialize` method of GraphQL type
* definition.
*
* If the field is an abstract type, determine the runtime type of the value
* and then complete based on that type
*
* Otherwise, the field type expects a sub-selection set, and will complete the
* value by evaluating all sub-selections.
*/
function completeValue(
exeContext: ExecutionContext,
returnType: GraphQLType,
fieldNodes: Array,
info: GraphQLResolveInfo,
path: ResponsePath,
result: mixed
): mixed {
// If result is a Promise, apply-lift over completeValue.
const promise = getPromise(result);
if (promise) {
return promise.then(
resolved => completeValue(
exeContext,
returnType,
fieldNodes,
info,
path,
resolved
)
);
}
// If result is an Error, throw a located error.
if (result instanceof Error) {
throw result;
}
// If field type is NonNull, complete for inner type, and throw field error
// if result is null.
if (returnType instanceof GraphQLNonNull) {
const completed = completeValue(
exeContext,
returnType.ofType,
fieldNodes,
info,
path,
result
);
if (completed === null) {
throw new Error(
`Cannot return null for non-nullable field ${
info.parentType.name}.${info.fieldName}.`
);
}
return completed;
}
// If result value is null-ish (null, undefined, or NaN) then return null.
if (isNullish(result)) {
return null;
}
// If field type is List, complete each item in the list with the inner type
if (returnType instanceof GraphQLList) {
return completeListValue(
exeContext,
returnType,
fieldNodes,
info,
path,
result
);
}
// If field type is a leaf type, Scalar or Enum, serialize to a valid value,
// returning null if serialization is not possible.
if (isLeafType(returnType)) {
return completeLeafValue(returnType, result);
}
// If field type is an abstract type, Interface or Union, determine the
// runtime Object type and complete for that type.
if (isAbstractType(returnType)) {
return completeAbstractValue(
exeContext,
returnType,
fieldNodes,
info,
path,
result
);
}
// If field type is Object, execute and complete all sub-selections.
if (returnType instanceof GraphQLObjectType) {
return completeObjectValue(
exeContext,
returnType,
fieldNodes,
info,
path,
result
);
}
// Not reachable. All possible output types have been considered.
throw new Error(
`Cannot complete value of unexpected type "${String(returnType)}".`
);
}
/**
* Complete a list value by completing each item in the list with the
* inner type
*/
function completeListValue(
exeContext: ExecutionContext,
returnType: GraphQLList<*>,
fieldNodes: Array,
info: GraphQLResolveInfo,
path: ResponsePath,
result: mixed
): mixed {
invariant(
isCollection(result),
`Expected Iterable, but did not find one for field ${
info.parentType.name}.${info.fieldName}.`
);
// This is specified as a simple map, however we're optimizing the path
// where the list contains no Promises by avoiding creating another Promise.
const itemType = returnType.ofType;
let containsPromise = false;
const completedResults = [];
forEach((result: any), (item, index) => {
// No need to modify the info object containing the path,
// since from here on it is not ever accessed by resolver functions.
const fieldPath = addPath(path, index);
const completedItem = completeValueCatchingError(
exeContext,
itemType,
fieldNodes,
info,
fieldPath,
item
);
if (!containsPromise && getPromise(completedItem)) {
containsPromise = true;
}
completedResults.push(completedItem);
});
return containsPromise ? Promise.all(completedResults) : completedResults;
}
/**
* Complete a Scalar or Enum by serializing to a valid value, returning
* null if serialization is not possible.
*/
function completeLeafValue(
returnType: GraphQLLeafType,
result: mixed
): mixed {
invariant(returnType.serialize, 'Missing serialize method on type');
const serializedResult = returnType.serialize(result);
if (isNullish(serializedResult)) {
throw new Error(
`Expected a value of type "${String(returnType)}" but ` +
`received: ${String(result)}`
);
}
return serializedResult;
}
/**
* Complete a value of an abstract type by determining the runtime object type
* of that value, then complete the value for that type.
*/
function completeAbstractValue(
exeContext: ExecutionContext,
returnType: GraphQLAbstractType,
fieldNodes: Array,
info: GraphQLResolveInfo,
path: ResponsePath,
result: mixed
): mixed {
const runtimeType = returnType.resolveType ?
returnType.resolveType(result, exeContext.contextValue, info) :
defaultResolveTypeFn(result, exeContext.contextValue, info, returnType);
const promise = getPromise(runtimeType);
if (promise) {
return promise.then(resolvedRuntimeType =>
completeObjectValue(
exeContext,
ensureValidRuntimeType(
resolvedRuntimeType,
exeContext,
returnType,
fieldNodes,
info,
result
),
fieldNodes,
info,
path,
result
)
);
}
return completeObjectValue(
exeContext,
ensureValidRuntimeType(
((runtimeType: any): ?GraphQLObjectType | string),
exeContext,
returnType,
fieldNodes,
info,
result
),
fieldNodes,
info,
path,
result
);
}
function ensureValidRuntimeType(
runtimeTypeOrName: ?GraphQLObjectType | string,
exeContext: ExecutionContext,
returnType: GraphQLAbstractType,
fieldNodes: Array,
info: GraphQLResolveInfo,
result: mixed
): GraphQLObjectType {
const runtimeType = typeof runtimeTypeOrName === 'string' ?
exeContext.schema.getType(runtimeTypeOrName) :
runtimeTypeOrName;
if (!(runtimeType instanceof GraphQLObjectType)) {
throw new GraphQLError(
`Abstract type ${returnType.name} must resolve to an Object type at ` +
`runtime for field ${info.parentType.name}.${info.fieldName} with ` +
`value "${String(result)}", received "${String(runtimeType)}".`,
fieldNodes
);
}
if (!exeContext.schema.isPossibleType(returnType, runtimeType)) {
throw new GraphQLError(
`Runtime Object type "${runtimeType.name}" is not a possible type ` +
`for "${returnType.name}".`,
fieldNodes
);
}
return runtimeType;
}
/**
* Complete an Object value by executing all sub-selections.
*/
function completeObjectValue(
exeContext: ExecutionContext,
returnType: GraphQLObjectType,
fieldNodes: Array,
info: GraphQLResolveInfo,
path: ResponsePath,
result: mixed
): mixed {
// If there is an isTypeOf predicate function, call it with the
// current result. If isTypeOf returns false, then raise an error rather
// than continuing execution.
if (returnType.isTypeOf) {
const isTypeOf = returnType.isTypeOf(result, exeContext.contextValue, info);
const promise = getPromise(isTypeOf);
if (promise) {
return promise.then(isTypeOfResult => {
if (!isTypeOfResult) {
throw invalidReturnTypeError(returnType, result, fieldNodes);
}
return collectAndExecuteSubfields(
exeContext,
returnType,
fieldNodes,
info,
path,
result
);
});
}
if (!isTypeOf) {
throw invalidReturnTypeError(returnType, result, fieldNodes);
}
}
return collectAndExecuteSubfields(
exeContext,
returnType,
fieldNodes,
info,
path,
result
);
}
function invalidReturnTypeError(
returnType: GraphQLObjectType,
result: mixed,
fieldNodes: Array
): GraphQLError {
return new GraphQLError(
`Expected value of type "${returnType.name}" but got: ${String(result)}.`,
fieldNodes
);
}
function collectAndExecuteSubfields(
exeContext: ExecutionContext,
returnType: GraphQLObjectType,
fieldNodes: Array,
info: GraphQLResolveInfo,
path: ResponsePath,
result: mixed
): mixed {
// Collect sub-fields to execute to complete this value.
let subFieldNodes = Object.create(null);
const visitedFragmentNames = Object.create(null);
for (let i = 0; i < fieldNodes.length; i++) {
const selectionSet = fieldNodes[i].selectionSet;
if (selectionSet) {
subFieldNodes = collectFields(
exeContext,
returnType,
selectionSet,
subFieldNodes,
visitedFragmentNames
);
}
}
return executeFields(exeContext, returnType, result, path, subFieldNodes);
}
/**
* If a resolveType function is not given, then a default resolve behavior is
* used which tests each possible type for the abstract type by calling
* isTypeOf for the object being coerced, returning the first type that matches.
*/
function defaultResolveTypeFn(
value: mixed,
context: mixed,
info: GraphQLResolveInfo,
abstractType: GraphQLAbstractType
): ?GraphQLObjectType | Promise {
const possibleTypes = info.schema.getPossibleTypes(abstractType);
const promisedIsTypeOfResults = [];
for (let i = 0; i < possibleTypes.length; i++) {
const type = possibleTypes[i];
if (type.isTypeOf) {
const isTypeOfResult = type.isTypeOf(value, context, info);
const promise = getPromise(isTypeOfResult);
if (promise) {
promisedIsTypeOfResults[i] = promise;
} else if (isTypeOfResult) {
return type;
}
}
}
if (promisedIsTypeOfResults.length) {
return Promise.all(promisedIsTypeOfResults).then(isTypeOfResults => {
for (let i = 0; i < isTypeOfResults.length; i++) {
if (isTypeOfResults[i]) {
return possibleTypes[i];
}
}
});
}
}
/**
* If a resolve function is not given, then a default resolve behavior is used
* which takes the property of the source object of the same name as the field
* and returns it as the result, or if it's a function, returns the result
* of calling that function while passing along args and context.
*/
export const defaultFieldResolver: GraphQLFieldResolver =
function (source, args, context, info) {
// ensure source is a value for which property access is acceptable.
if (typeof source === 'object' || typeof source === 'function') {
const property = source[info.fieldName];
if (typeof property === 'function') {
return source[info.fieldName](args, context, info);
}
return property;
}
};
/**
* Only returns the value if it acts like a Promise, i.e. has a "then" function,
* otherwise returns void.
*/
function getPromise(value: Promise | mixed): Promise | void {
if (typeof value === 'object' &&
value !== null &&
typeof value.then === 'function') {
return (value: any);
}
}
/**
* This method looks up the field on the given type defintion.
* It has special casing for the two introspection fields, __schema
* and __typename. __typename is special because it can always be
* queried as a field, even in situations where no other fields
* are allowed, like on a Union. __schema could get automatically
* added to the query type, but that would require mutating type
* definitions, which would cause issues.
*/
export function getFieldDef(
schema: GraphQLSchema,
parentType: GraphQLObjectType,
fieldName: string
): ?GraphQLField<*, *> {
if (fieldName === SchemaMetaFieldDef.name &&
schema.getQueryType() === parentType) {
return SchemaMetaFieldDef;
} else if (fieldName === TypeMetaFieldDef.name &&
schema.getQueryType() === parentType) {
return TypeMetaFieldDef;
} else if (fieldName === TypeNameMetaFieldDef.name) {
return TypeNameMetaFieldDef;
}
return parentType.getFields()[fieldName];
}